Chlorofluorocarbons (CFCs) such as R-11, R-12, R-113, R-114, R-115 and blends containing these CFCs such as R-500 and R-502 are currently used as refrigerants. Because of the great chemical stability of CFCs, when they are released into the atmosphere only minuscule fractions are destroyed by natural processes in the troposphere. As a result, CFCs have long atmospheric lifetimes and migrate to the stratosphere where they undergo photolysis, forming chlorine radicals that seriously deplete the earth's protective ozone layer. When R-12 (dichlorodifluoromethane) is eventually released into the atmosphere, it rises to the stratosphere, where it is struck by ultraviolet radiation. This causes the R-12 to decompose to give chlorine radicals that catalytically destroy the protective ozone layer of the earth. This depletion of stratospheric ozone allows more ultraviolet light to reach the surface of the earth, resulting in increases in human skin cancer and cataracts plus damage to crops and natural ecosystems. This invention will significantly decrease these adverse effects by providing a lubricant suitable for use with an environmentally safe alternative agent, carbon dioxide, to use in place of the CFCs.
U.S. Pat. No. 4,111,821 (Lazarus et al., Sep. 5, 1978) discloses lubricant compositions for use in the cylinder and drive train lubrication of reciprocating compressors for oxygen-free gases comprise 97% to 99% by weight of a base fluid that is a phthalate ester of an aliphatic alcohol having 10 to 15 carbon atoms and 1% to 3% by weight of an additive system that contains a viscosity index modifying component, an antioxidant component, and optionally a corrosion inhibitor and/or a load bearing additive.
U.S. Pat. No. 4,238,343 (Pellegrini, Jr., Dec. 9, 1980) relates to synthetic oils useful for the insulation of electrical apparatus and more particularly it relates to the preparation and use in electrical power transformers of novel mono- and dialkylates of an aromatic compound in which the alkylate portion is an oligomer of a four to 12 carbon alpha-olefin containing predominantly at least about 30 carbon atoms up to about 60 carbon atoms.
U.S. Pat. No. 4,420,946 (Rojey et al., Dec. 20, 1983) relates to refrigeration machines using the vaporization of a refrigeration fluid to produce cold. In conventional 1-stage installations, the refrigeration fluid in vapor phase is compressed, condensed with heat delivery to an external fluid, most often water or air, and then expanded and supplied to the vaporization step.
U.S. Pat. No. 4,737,297 (Yoshida et al., Apr. 12, 1988) consists of, or comprises as the main component, at least one monosubstituted naphthalene derivative represented by the following general formula ##STR1##
wherein R.sub.1, R.sub.2 and R.sub.3 may be identical with, or different from, each other and are each an alkyl, phenyl or alkylphenyl group having 1 to 21 carbon atoms with the proviso that the total of carbon atoms of R.sub.1, R.sub.2 and R.sub.3 is 4-23.
U.S. Pat. No. 4,963,280 (Wilkens et al., Oct. 16, 1990) relates to the improvement in the energy efficiency of heat pump systems including refrigeration units, heating and air conditioning systems which pump heat from one location to another.
Typical heat pump systems rely upon a compressible fluid to transfer the heat from one location to another. The most common heat transfer media are the members of the Freon family as well as ammonia. Ammonia finds particular application in large scale refrigeration systems such as cold storage units and the like. In addition to these two classes of heat transfer media or compressible fluids, other compressible fluids may be utilized which undergo phase changes under reasonable changes of pressure. Such compressible fluids which undergo the necessary change from liquid to gaseous states by the change in pressure are well known in the art and include gases such as carbon dioxide. In general, the selection of the heat transfer media is dependent upon a number of design criteria which are well known. In general, for commercial installations the use of either Freon or ammonia is most preferred. However in specially applications media such as carbon dioxide may be utilized.
U.S. Pat. No. 4,983,313 (Kaneko et al., Jan. 8, 1991) discloses a refrigerating machine oil composition comprising:
(A) 85 to 30% by weight of alkyl benzene having a kinematic viscosity at 40.degree. C. of 30 cSt or more; PA1 (B) 5 to 70% by weight of a paraffin-based mineral oil having a kinematic viscosity at 40.degree. C. of 20 to 500 cSt, a pour point of -35.degree. C. or lower, a viscosity index of 60 or more, and a sulfur content of 100 ppm or less; and PA1 (C) 1 to 30% by weight of a naphthene-based mineral oil having a kinematic viscosity at 40.degree. C. of 5 to 500 cSt, a pour point of -30.degree. C. or lower, and a sulfur content of 0.05 to 1% by weight, the total sulfur content of said composition being 0.01 to 0.10% by weight. PA1 (A) carbon dioxide refrigerant, and PA1 (B) a lubricant of an aliphatic substituted naphthalene.
The present composition is excellent in stability, lubricity, compatibility with refrigerants, and low temperature property.
U.S. Pat. No. 5,279,752 (Hasegawa et al., Jan. 18, 1994) of the present invention relates to compositions useful as lubricating oil for refrigerants.
As the refrigerants for the refrigerating machines having a type of compressing the vapor of the refrigerant, there are widely used halogenated hydrocarbons typified by trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), monochlorodifluoromethane (HCFC-22), trichlorotrifluoroethane (CFC-113) or the like, hydrocarbons, in which propane is a typical substance, and inorganic gases typified by ammonia, carbon dioxide or the like.
As lubricating oils for the refrigerating machines using such refrigerants, there are generally used paraffinic mineral oils, naphthenic mineral oils, alkylbenzenes, poly-.alpha.-olefins, oils consisting of polyoxyalkylene and/or polyalkylene glycol compounds and a mixture of two or more of these oils, or oils obtained by adding one or more additives to these base oils.
U.S. Pat. No. 5,344,582 (Umemoto et al., Sep. 6, 1994) relates to a traction fluid lubricant is disclosed which contains a naphthenic ingredient having a weight average molecular weight of 200-300 and obtained by hydrogenating oligomers of cyclopentadiene having a ratio of the number of norbornenic double bond to that of cyclopentenic double bond of smaller than 0.9 but not smaller than 0.1. The naphthenic ingredient is suitably used in conjunction with an auxiliary ingredient selected from a polybutene having a viscosity of 5-60 cSt at 40.degree. C. and a bicyclohexyl compound.
U.S. Pat. No. 5,512,198 (Sasaki et al., Apr. 30, 1996) relates to when a fluoroalkane is used as a refrigerant and an ester oil, polyalkylene glycol oil or the like is used as a refrigerator oil. As a result, it has been found that a refrigerator oil composition capable of exhibiting excellent abrasion resistance and therefore practically usable can be obtained by incorporating a boron compound in the refrigerator oil.
The reference therefore provides a refrigerator oil composition for a fluoroalkane refrigerant which comprises a base oil composed principally of an oxygen-containing compound and 0.005-5.0 wt. %, based on the total weight of the composition, of a boron compound as an essential component.
U.S. Pat. No. 5,716,549 (Nimitz et al., Feb. 10, 1998) relates to a new set of effective, environmentally safe, nonflammable, low-toxicity refrigerants, solvents, foam blowing agents, propellants, and firefighting agents is disclosed. The agents are clean, electrically nonconductive, and have short atmospheric lifetimes, zero ozone-depletion potential, and low global warming potentials. The agents comprise at least one fluoroiodocarbon agent satisfying the general formula C.sub.a H.sub.b Br.sub.c Cl.sub.d F.sub.e I.sub.f N.sub.g O.sub.h, wherein a is between and including 1 and 8; b is between and including 0 and 2; c, d, g, and h are each between and including 0 and 1; e is between and including 1 and 18; and f is between and including 1 and 2, either neat or mixed with additives selected from the group consisting of: alcohols, esters, ethers, fluoroethers, hydrocarbons, hydrofluorocarbons, and perfluorocarbons.
U.S. Pat. No. 5,817,251 (Takigawa et al., Oct. 6, 1998) relates to a refrigerating machine oil (a refrigerating machine lubricating oil), a fluid composition for use in a refrigerating machine, a refrigerating machine using therein a hydrofluorocarbon refrigerant with said refrigerator oil and a method of lubricating a cooling system. More particularly, this invention relates to a refrigerating machine oil which comprises as least one hydrocarbon compound having a specific structure and is suitable for use with a hydrofluorocarbon (HFC) refrigerant, to a fluid composition for use in a refrigerating machine, which comprises the hydrofluorocarbon refrigerant and the refrigerating machine oil, to a refrigerating machine using therein the above-mentioned fluid composition and to a method of lubricating a cooling system of a refrigerating machine using therein the hydrofluorocarbon (HFC) as a refrigerant, characterized by using the refrigerator oil as a lubricating oil in said cooling system.
U.S. Pat. No. 5,847,246 (Hsu et al., Dec. 8, 1998) relates to heat transfer processes at low temperatures, to low temperature heat transfer fluids, and more particularly, to processes for the transfer of thermal energy at temperatures significantly below zero Fahrenheit by means of a specially formulated low temperature heat transfer fluid.
The heat transfer fluid of this reference is comprised of a mixture selected from a group of mixtures containing at least two monocyclic terpenes, at least two bicyclic terpenes, or at least one monocyclic terpene and at least one bicyclic terpene. Regardless of the selection, the respective components (monocyclic or bicyclic terpenes) are provided in an effective amount to retain the liquid phase of the mixture comprising the heat transfer fluid at a temperature in the range from about 0.degree. F. to between about -110.degree. F. and -165.degree. F.
U.S. Pat. No. 5,858,930 (Dasai et al., Jan. 12, 1999) provides compounds of formula (I): ##STR2##
wherein R.sup.1 and R.sup.2 are each independently selected from branched alkyl groups containing 7 to 8 carbon atoms and alkyloxylalkyl groups containing 4 to 24 carbon atoms.
In accordance with this reference, by selection of the substituents R.sup.1 and R.sup.2 of the 1,8-naphthalimide ring structure, a dye can be obtained that has excellent stability in lubricant compositions under a refrigeration cycle environment while simultaneously providing sufficient fluorescent efficiency. R.sup.1 and R.sup.2 are "independently selected," meaning that they may be the same or different. The substituent groups represented by R.sup.1 and R.sup.2 are a branched alkyl group containing 7 or 8 carbon atoms or an alkyloxyalkyl group containing 4 to 24 carbon atoms. The branched alkyl groups include single and multiple branching.